This invention is directed to a method of waving hair and to a silicone based neutralizer composition useful in the permanent waving of hair.
Keratin is a fibrous protein composed of eighteen different kinds of amino acids. It is widely distributed in hair and constitutes the major component thereof. Keratin is characterized by a crosslinked structure having one disulfide bond (--S--S--) per average ten to twenty amino acid residues. It is most frequently represented as cystine which has the formula HO.sub.2 CC(NH.sub.2)HCH.sub.2 S--SCH.sub.2 C(NH.sub.2)HCO.sub.2 H.
The first basic step in a permanent waving process is the partial reduction of cystine HO.sub.2 CC(NH.sub.2)HCH.sub.2 S--SCH.sub.2 C(NH.sub.2)HCO.sub.2 H to cysteine HO.sub.2 CC(NH.sub.2)HCH.sub.2 SH. Typically, a waving lotion containing thioglycolic acid is used in this step, in a reaction in which cystine bridges are reduced to cysteine. After the hair has been reshaped, this reaction is reversed by the application to the hair of a neutralizer, which is a solution containing an oxidant such as hydrogen peroxide. Cysteine residues formed during the reduction step are converted back into cystine upon neutralization.
While hydrogen peroxide is environmentally safe and physiologically harmless, it suffers from the disadvantages that (i) special stabilizers are required to assure stability; (ii) complexing agents are needed to bind up metallic impurities which may have a catalytic effect; and (iii) hair can be lightened at certain concentrations and pH values.
Thus, a need exists in the art for alternative forms of permanent wave neutralizer compositions. The present invention provides such an alternative in the form of a silicone based composition which has been found to effectively function as a keratin crosslinking agent in the permanent waving of human hair.
It is believed that the silicone becomes part of a covalent crosslink between hair keratin fibers in providing a wave. In addition, use of the silicone has the advantage that the silicone imparts to the hair added benefits such as conditioning of the hair as well providing softness of feel.